* {
  margin: 0;
  padding: 0;
}

body {
  width: 100vw;
  height: 100vh;
  overflow: hidden;
  display: flex;
  justify-content: center;
  align-items: center;
  position: relative;
  background-color: rgb(7, 7, 7);
}

#main-canva {
  background: url(../img/yy/bj.jpg);
  background-size: 100% 100%;
  /* background-position-y: 100%; */
  animation: backrol 20s linear infinite;
  position: relative;
}

@keyframes backrol {
  0% {
    background-position-y: 0px;
  }
  100% {
    background-position-y: 710px;
  }
}
